Various acoustic devices incorporate active noise reduction (ANR) features, also known as active noise control or cancellation (ANC), in which one or more microphones detect sound, such as exterior acoustics captured by a feedforward microphone or interior acoustics captured by a feedback microphone. Signals from a feedforward microphone and/or a feedback microphone can be processed to provide anti-noise signals to be fed to an acoustic transducer (e.g., a speaker, driver) to counteract noise that may otherwise be heard by a user. Feedback microphones may pick up acoustic signals produced by the transducer and form a closed loop system that could become unstable at times or under certain conditions.